1. Field of the Invention
The invention relates to an inkjet print control apparatus and, more particularly, to an inkjet print control apparatus using a simple instruction to read non-successive print data.
2. Description of Related Art
Currently, inkjet printers capable of providing color printing are in wide spread use as multimedia is becoming popular rapidly. Because the inkjet printers can print multiple lines at a time, and to meet with the mechanical features of nozzle arrangement of inkjet head or other hardware features, print image data is not fetched line by line in up-down sequence but by regular or irregular branch. To achieve this, a processor in an inkjet printer or a personal computer (PC) connected to the inkjet printer requires performing pre-sequencing arrangement, which occupies processor time and bus bandwidth in the inkjet printer or the PC.
As shown in FIG. 1, a typical memory arrangement for image data is to store horizontally adjacent pixels in a memory. Every address of the memory has a word of four bytes. Namely, as a pixel has four bits, the adjacent pixels are stored in a next address after eight pixels occupy a word.
When a printer prints multiple lines at a time, it has to read non-successive addresses in the memory because print data is located in different lines. In addition, a pixel data of a word is used in each time. For an example of print data after halftone process, a pixel data only occupies one or few bits of memory space. For a memory width of 16 bits, each read from a 16-bit data can have only one available bit (a pixel data), since only one pixel data is required for a line. Accordingly, 16 times of read operations are required for completely reading the horizontal 16 pixels data, which wastes time and also occupies the common memory bandwidth to be used by other processors. Similarly, a longer memory width, such as 32 bits, may waster more time and bandwidth.
To overcome this, U.S. Pat. No. 6,298,332 applies programmable timing profile to adjust associated timing control of different inkjet heads. However, this cannot overcome the problem caused by printing multiple lines at a time, as the processor in the inkjet printer or the PC has to convert raw data of image into a format capable of meeting with the sequence of inkjet heads in advance. Such a conversion requires software operations including heavy bit operation and the operation speed is slow. When a specific processor is applied to the conversion, the performance is increased due to job division but the operation speed is still slow. Therefore, it is desirable to provide an improved device to mitigate and/or obviate the aforementioned problems.